Edje Objects: Managing Layouts and Layout Components

You can build and handle layouts using Edje objects. An Edje object is a type of Evas object for displaying units, such as rectangles, lines, polygons, text, and images. Edje objects are only used in Edje and provide functions that deal with Edje layouts and layout components. Namely, there is no Edje object type in the source code for implementing an application. The objects are mainly layouts or themes defined by groups and parts, and declared in EDC files.

Edje provides functions for the following features:

• Handling Edje Files

  Edje layouts are called themes and created using the EDC language. The EDC language is declarative and must be compiled before being used. The output of this compilation is an EDJ file, which can be loaded by Edje, and the result is an Edje object.

• Scaling Edje Objects

  Edje enables you to build scalable interfaces. There are 2 types of scaling factors, which are set to neutral (1.0) values by default (no scaling, actual sizes): global and individual. Scaling affects the minimum and maximum values of the part sizes, which are multiplied. Font sizes are scaled, too.

• Using Edje Color Classes

  To change the color and text of 2 or more parts simultaneously, you can use color classes. If parts are assigned with a color class, setting the color values to this class causes all the parts to have their colors multiplied by the values. Setting the values to a color class at a process level affects all parts with that color class, while at the object level, only the parts inside a specified object are affected.

• Using Edje Text Classes

  To change the text of 2 or more parts simultaneously, you can use text classes. If parts are assigned with a text class, setting the font attributes to this class updates all these parts with the new font attributes. Setting the values to a text class at a process level affects all parts with that text class, while at the object level, only the parts inside a specified object are affected.

• Using Edje Perspective

  Perspective is a graphical tool that makes 2D objects appear as 3D. The perspective can be used with all Edje objects.

• Managing Signals and Messages

  Edje objects have 2 communication interfaces between the logic and GUI. You can either emit a signal from the logic to the GUI, or create handles for the signals emitted from the GUI. Signals are identified by strings. With Edje messages, you can communicate values, such as strings, float numbers, and integer numbers. Messages can also be identified by integer numbers.

• Managing Edje Animations

  Edje has the ability to animate their objects. You can start, stop, play, pause, freeze, and thaw Edje animations, and check their status.